Improvement in apparatus for enlarging and reducing prints



N`.173,7z0 patented Feb. 22,1816;

n mw UNITED STATES PATENT ortica vICToR GUERIN, on PARIS, FRANCE.

IMPROVEMENT `|N APPARATUS FOR ENLARclNG AND Ri-:DuclNe PRINTS.

Specification forming part of Letters Patent No. 173.720, dated February 22, 1876; application filed octotr 11, 1875.

To all whom it may concern:

Be it known that I, VICTOR GUERIN, of

Paris,rFrance, have invented Improved Ap! paratus for Enlargiug and Reducing Designs,

Prints, and otherdel'ineations; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the annexed drawing, making apart of the same.

This inventionrelates toimproved apparatus for reducing or enlarging drawings, deslgns, labels, lithographie, typographic, and

other prints. rllhe reduction and enlargement of such designs are usually effected by hand, which 1s a tedious and expensive process, re-

quiring 'the aid of specially skilled labor. An apparatusl has, however, already been devised for the purpose, composed of a thin sheet of india-rubber, of square form,beariug the del 4 sign to be reduced or enlarged.

In making a reduction, the elastic'sheet is stretched previous to the application of thel the square form of the elastic sheet, the tension is irregular, being greater near the middle of the four sides than at the four angles, in consequence of which the design is distorted instead of being uniformly acted on at all parts.

The presentinvention is designed to obviate these objections, the apparatus being of simple construction, and so arranged that any print or design may be rapidly reduced or enlarged without liability of distortion.

The apparatus is composed of two metal rings, forming a circular frame, between which is firmly clamped a circular sheet of india-rubber, thickened around its circumference to form a kind of beveled edge. This elastic sheet is drawn over a fixed disk or circular table mounted on the end of a screw-pillar ixed upon a suitable pedestal. On this screw a nut is causedto travel up and down by means of hand-wheel, or otherwise, said nut being fitted to turn freely between collars on a plate, to which is attached the circular frame in which the elastic sheet is clamped, so that the frame will be caused to move up and down `with the nut without partaking of its rotary motion. The whole being thus arranged to distend the sheet, the nut is turned so as t0 draw down the said frame, and with it the edge ofthe sheet, whereby it is stretched over the fixed disk or table above mentioned, the extent to which the sheet is stretched being regulated by the distance traversed by the nut upon the screw. It will be seen that the elastic sheet will be uniformly distended, as the tension is equally applied at all parts of its circumference, and therefore perfectly correct reductions or enlargements of the design, transferred onto the sheet of india-rubber, will be obtained.

It will be understood that the disk, instead of being fixed, may be movable, the screw only being made to turn, the nut remaining stationary. Instead of a screw, a rack or other mechanical equivalent may be employed.

l The rise and fall of the disk for stretching the elastic sheet` may also be` obtained by means of an arrangement of spiral springs, which are compressed and retained in that position. The design being applied upon the elastic sheet, the springs are then released., so as to raise the disk and distend the india-rubber,.

whereby the design becomes enlarged. rIhe action is reversed if the design is to be reduced.

Further, in order that the elastic sheet may be unifor mly stretched in every direction, and

to insure that it bears properly upon the disk,

I may blow or force air into the chamber formed beneath the sheet of india-rubber, at an openin g provided for the purpose, whereby the elastic sheet is raised and detached from the stretching-disk, so that its free extension or contraction is not impeded by its adhesion to the said disk.

The invention isv illustrated in the accompanying drawings, which show two arrangements of the' apparatus, by way 0f example only.

thereon, and surniounted by the stretching disk c; d, nut traveling on b e, wheel with handlesffor turning nut d; g, plate in which nut d is fitted to turn loosely, as shown. To

rthis plate is affixed ring h, between which and another ring, yi, the edge of the elastic sheetj is clamped by the'aid of bolts 7c, or a circular groove may be made around the plate g, and the edge of the elastic sheet be secured either by a'ligature or by an elastic ring. The central portion of the sheet, onto which' the design is to be transferred, is made-of thin Aindia-rubber, While the outer portion, which does not require to be stretched radially, is made of rubber coated fabric, which will stretch circularly, but not otherwise. Z is an aperture for supplying air to the under side of the elastic sheet, or a passage may be made in the foot a and the screw b for the same purpose. The aperture l is closed by a plug.

Figs. 4 and 5 of the drawing show the modication ofthe apparatus, which differs'froinv that above described only in certain details, designed to facilitate the use ofthe apparatus. These modifications relate, trst, to the fixed disk or table, which is encircled by a removable ring, for a purpose hereinafter described; second, to the substitution of a valve for the plug shown in the former arrangement; and, third, to the employment of two hoops or bands, the one for clamping the edges ofthe elastic sheet to the movable plate, and the other for retaining the sheet when distended upon the removable ring, which is then detached from the disk for the purpose of transferring the design to stone.

rlhe apparatus represented in Figs. 4 and 5 is to be made with a foot, a screw-pillar mounted thereon, and surinounted by the sta` Vtional-y disk, with a nut traveling on the screw; with a movable plate in which the lint is itted to turn loosely, and with handles for turning the n'ut, the same as heretofore described. l is a valve for inlet and exit of air through hole l fitted onto the plate g; h, a

-ring encircling the stationary disk;'ix, ahoop for clamping the edges of the elastic sheet to the rim of plate g; o", a hoop for securing the said sheet in its distended condition upon ring hx.

The following is the action of the apparatus: To enlarge, it isfirst necessary to produce the design upon the elastic sheet j, which is then secured by its edges to the plate g by means of the hoop ix. rlhis is done while the plate g is in the raised position, Fig. 5, and the nut d is then turned by handles f to draw down the plate g until the elastic sheet is sufficiently distended. During the descent of the plate lair enters at valve l", which opens automatically. The elastic sheet j having been thus stretched, and the design thereon correspondingly enlarged, the hoop 4o is then applied and tightened up, if necessary, so as to'rmly retain the elastic sheet upon ring h". The plate g is now raised to release the edges'of the sheet from tension, and en-able it'to be de'- tached from the plate by removing the hoop i* but before doing this the valve l is raised to allow'the airy within lto escape. The -central part only of the elastic sheet being now retained by the hoop 0 upon ring It* the latter is removed, as shown in F-ig'. 6, in order to transfer or apply the enlarged design in any convenient manner to the stone, which is then prepared for obtaining prints by the ordinary means employed in lithography.

In order to reduce a drawing or design the action is reversed-that is to say, the elastic sheet is stretched'beforc the design is applied or traced thereon, and on releasingy the sheet the reduction is effected.

I claim as my inventionl. rlhe combination of the ixed circular plate c, movable circular plate g, and clamping-ring t', with each other, for extending or contracting a circularelastic sheet, constructed substantially as specified.

2. The rings hx and 0X, combined with the plates c and g of a sheet distendingand contracting apparatus, constructed substantially as specilied.

3. The air-opening L applied to the plate gof a sheet distending and contracting apparatus, constructed substantially as specified.

VICTOR GUERIN. Witnesses:

RoB'r. M. HoorER, A(JHARLEs DEsNos, ADoLPHE GUIoN. 

